This pretty simple bracket is designed to fit to the JGAurora A5's frame using the bed level screws as attachment points. You just have to un-screw one of your levelling screws, id suggest the front right, slide the long arm piece into the bed frame and then re-tighten the bed screw. use a little superglue to hold the arm tightly.
It then attaches to the official raspberry Pi Zero (and Zero W) case using the slot on the rear that's designed for the camera ribbon cable, its just a friction fit.
The bracket has freedom using the circular pins to adjust the tilt angle and left-right direction the camera faces. Once you've found the angle that's good, just squeeze the pin into the hole. They're both exactly 6mm wide so again, its a friction fit.
Everything has been measured so that in any "sensible" position of the Pi,it shouldn't come into contact with any of the axis, or the frame, just be careful with how you adjust the tilt and rotation of this bracket. If you put it at some stupid angle, you could hit the Z axis, or the frame,.
As for power and data to the RPI, you can run them internally using a 24v to 5c converter and by unplugging the internal USB connection, but that was overkill for me. I just use an external wall powered USB charger and connect a short OTG to USB Type B cable that I connect to the side printer port. As long as the bed can still travel its full distance, the cable is OK to be external.
Before assembly, run a 6mm drill bit into all the holes, this ensures they're truly round and the right size.
The longer of the two arms attaches to the print bed using a bed level screw and should leave you with a 6.. hole to the right side (not the left as that will take it into the print bed frame/base part!)
The short of the two arms attaches to the longer one using the small "barrel" shaped connector. Set the angle, the squeeze the barrel connector pin into the corresponding holes on the arms.
The piece with the flat shovel connects to the RPI Zero. The shovel shape piece goes into the ribbon cable hole on the rear of the official RPI Zero case, again, the Pin goes into the remaining hole and lets you set the left/right angle. You may want to glue the shovel shaped piece into the RPI case.